123242551 has 4 divisors (see below), whose sum is σ = 123722352. Its totient is φ = 122762752.

The previous prime is 123242549. The next prime is 123242617. The reversal of 123242551 is 155242321.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 123242551 - 2¹ = 123242549 is a prime.

It is a super-5 number, since 5×123242551⁵ (a number of 42 digits) contains 55555 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123242851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239515 + ... + 240028.

It is an arithmetic number, because the mean of its divisors is an integer number (30930588).

Almost surely, 2^123242551 is an apocalyptic number.

123242551 is a deficient number, since it is larger than the sum of its proper divisors (479801).

123242551 is an equidigital number, since it uses as much as digits as its factorization.

123242551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 479800.

The product of its digits is 2400, while the sum is 25.

The square root of 123242551 is about 11101.4661644307. The cubic root of 123242551 is about 497.6456662920.

Adding to 123242551 its reverse (155242321), we get a palindrome (278484872).

The spelling of 123242551 in words is "one hundred twenty-three million, two hundred forty-two thousand, five hundred fifty-one".